Interaction of polyadenylic acid (5') with histone H1 or protamine

The interaction between polyadenylic acid (5') (poly [A]) and histone (or protamine) was analyzed by electrophoretic retardation of poly [A]-histone (or protamine) complex in agarose gel. The potency of interaction was protamine > histone H1, arginine-rich histone > other histones. The catalytic subunit of cyclic AMP-dependent protein kinase effectively decreased the electrophoretic retardation of poly [A]-histone H1. The interaction between poly [A] and histone H1 was also detected by the drastically enhanced absorbance around 340 nm. The findings may implicate a regulatory role of histone H1 on mRNAs through its binding on poly [A] tails.